Glycerin
The most effective and best-studied humectant in skincare. Glycerin (glycerol) is a small molecule that penetrates the stratum corneum readily, drawing water from the atmosphere and deeper skin layers to hydrate the outer skin. Present in virtually every moisturizer and many serums. Studies show it rivals or outperforms hyaluronic acid for hydration efficacy at a fraction of the cost.
Concentration & Usage
Concentrations: 2-10% in most products (often higher in moisturizers). Pure glycerin is too sticky — always diluted in formulations. Works best below 20% concentration. No maximum daily use limit.
Application
Topical (present in virtually all moisturizers, serums, and toners). Apply as part of regular skincare routine.
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Mechanism of Action
Glycerin (glycerol) is a small three-carbon polyol (92 Da) that penetrates the stratum corneum via intercellular lipid and transcellular routes. It acts as a humectant through osmotic mechanisms—creating a concentration gradient that draws water from the atmosphere (when humidity >65%) and from deeper epidermal layers. Glycerin upregulates aquaporin-3 (AQP3), a glycerol-permeable water channel in keratinocyte membranes that facilitates water and glycerol transport. It supports the natural moisturizing factor (NMF)—amino acids, lactate, and urea that maintain stratum corneum water-holding capacity. Glycerin modulates keratinocyte differentiation and may enhance lipid lamellae organization. Mild antimicrobial activity occurs through osmotic stress. Clinical studies demonstrate hydration efficacy comparable to or exceeding hyaluronic acid.
Ingredient Interactions
Both draw moisture into the skin but through different mechanisms. Glycerin is a smaller molecule and provides consistent hydration; HA holds up to 1000x its weight in water at the surface.
See our full Ingredient Interactions Guide for more combinations and timing strategies.
Regulatory Status
GRAS ingredient. Cosmetic ingredient available worldwide. One of the oldest and most established humectants.
Risks & Safety
Common
Stickiness at high concentrations. May cause mild breakouts in some acne-prone individuals (varies by person).
Serious
None. Extremely safe.
Rare
Allergic reaction is extremely rare.
Compare Glycerin With
Research Papers
9Published: December 16, 2019
AI Summary
The Cosmetic Ingredient Review Expert Panel (Panel) reviewed relevant animal and human data. The Panel concluded that glycerin is safe as a cosmetic ingredient in the practices of use and concentration described in this safety assessment.
Published: March 22, 2020
AI Summary
In aged nursing care receivers, the prevalence of adverse skin conditions such as xerosis cutis, intertrigo, pressure ulcers or skin tears is high. Adequate skin care strategies are an effective method for maintaining and enhancing skin health and integrity in this population.
Published: March 23, 2019
AI Summary
Seborrheic dermatitis (SD) is a chronic, recurring inflammatory skin disorder that manifests as erythematous macules or plaques with varying levels of scaling associated with pruritus. SD treatment focuses on clearing signs of the disease; ameliorating associated symptoms, such as pruritus; and maintaining remission with long-term therapy.
Published: April 16, 2025
AI Summary
Acne and sensitive skin can take a profound toll on patients' well-being, which can be exacerbated if the conditions are experienced together. Moreover, some corrective procedures, e.g., injectable non-animal stabilized hyaluronic acid (NASHA) fillers, have proven effective for treating acne scarring.
Published: October 28, 2022
AI Summary
Topical agents and synthetic drugs used for dandruff treatment have specific side effects including burning at the application site, depression, dizziness, headache, itching or skin rash, nausea, stomach pain, vision change, vomiting, discoloration of hair, dryness or oiliness of the scalp and increased loss of hair.
Published: December 19, 2024
AI Summary
To investigate prognosis and clinical practices of infants born at 22-23 weeks' gestational age (wkGA) in Japan.
Published: July 1, 2022
AI Summary
Few cosmetic ingredients are shown to be able to safely remove or lighten facial dark spots once they have formed. OG has been reported to possess oxidation power and exhibit various biological activities such as antibacterial, antiviral, and wound healing promotion.
Published: July 11, 2021
AI Summary
Analysis of the structure of AGEs on the carbonylated proteins extracted from MGO-treated skin sections revealed that skin collagen had been converted to MG-H1-modified protein. These novel findings suggest that continuous application of MGO to the skin leads to carbonylation of proteins, which may cause prompt accumulation of MG-H1-modified der...
Published: December 22, 2024
AI Summary
There was also a significant difference in the improvement of skin hydration outcomes between both groups (p < 0.05). The severity of the disease using Scoring Atopic Dermatitis (SCORAD) showed a significant difference (p < 0.05) between the experiment group and the control group after 2 weeks of intervention.
Frequently Asked Questions
What is Glycerin used for?
The most effective and best-studied humectant in skincare. Glycerin (glycerol) is a small molecule that penetrates the stratum corneum readily, drawing water from the atmosphere and deeper skin layers to hydrate the outer skin. Present in virtually every moisturizer and many serums. Studies show it rivals or outperforms hyaluronic acid for hydration efficacy at a fraction of the cost.
What are the side effects of Glycerin?
Common: Stickiness at high concentrations. May cause mild breakouts in some acne-prone individuals (varies by person). Serious: None. Extremely safe. Rare: Allergic reaction is extremely rare.
How is Glycerin administered?
Glycerin is administered via topical (present in virtually all moisturizers, serums, and toners). apply as part of regular skincare routine..
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